Atmospheric water harvesting with scale‐up potentials using natural sunlight and passive cooling

Abstract Sorption‐based atmospheric water harvesting (SAWH) is a promising technology that can potentially alleviate global shortages of water, especially in arid regions. However, current SAWH devices are difficult to scale up and exhibit significant disadvantages in terms of their cost, portability and efficiency. Herein, we report a portable and efficient atmospheric water‐harvesting device with scalable and low‐cost high‐performance lithium‐containing membrane‐encapsulated composite sorbents. We use the thermodynamic framework for moist air states to develop the device with a structure featuring hollow insulation grid that harnessed the large temperature difference between the sorbent and the condenser, and thus, the water yield of SAWH device was increased by 20.5%. In outdoor experiments, it achieved an ultra‐high water productivity of 34.8 g water /kg device and 1399.28 g water /(m 2 day) and an exceptionally low water‐extraction cost of $2.65/kg water per cycle. Thus, this scalable and efficient passive SAWH device demonstrates the possibility of achieving low‐cost and reliable water production in real scenarios and paves the way for practical applications of SAWH. Key points Water harvesting cost‐efficient sorbent Heat and moisture transfer optimization